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The Cosmic Density and Distribution of Relativistic Iron Lines. David R. Ballantyne Center for Relativistic Astrophysics, School of Physics, Georgia Tech. 2010, ApJ, 708, L1. Motivation. Relativistic Fe K lines are v. important for probing the physics of the inner accretion flow
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The Cosmic Density and Distribution of Relativistic Iron Lines David R. Ballantyne Center for Relativistic Astrophysics, School of Physics, Georgia Tech 2010, ApJ, 708, L1
Motivation • Relativistic Fe K lines are v. important for probing the physics of the inner accretion flow • One of the few probes of SMBH spin Fabian, et al. (2002)
Motivation (II) • Accurate measurement of broad Fe K lines over a wide range of luminosity and z is one of the principle science goals of IXO • Spin evolution of SMBHs in the universe
Important Questions • How common are intense Fe K lines like that exhibited by MCG-6? • Does the EW depend on L and z? • The relative small number of decent detections of broad lines in local AGNs typically have EWs <~ 100 eV. Nandra et al. (2007)
Where do the Fe K lines come from? Ross & Fabian (1993), Ross et al. (1999), Ballantyne et al. (2001), Ross & Fabian (2005)
Photon-index Fe abundance AFe Ionization parameter ξ The Fe K EW Depends on: • Reflection fraction R (Ignored here: time-dependent effects, e.g., Ballantyne & Ross 2002, Ballantyne et al. 2005) Ballantyne et al. 2002
Survey Results: Metallicity Fe II/Hβ L/LEdd0.7 ; Netzer & Trakhtenbrot (2007)
Survey Results: Photon Index = 0.58(log(L/LEdd) +1) + 1.99 ; Risaliti et al. (2009)
Survey Results: Ionization Parameter ξ log(L/LEdd) ; Inoue et al. (2007)
Ueda et al. (2003) HXLF Other Ingredients • Netzer (2009) Type 1 AGN SMBH mass function at z=0.15 • Labita et al. (2009a) show that MBH(max) z0.3
The Fe K EW Function Ballantyne (2010)
Sky Density of Fe K Lines • If R=1, on average, then the most common Fe K EWs should be <~ 100 eV • A 1 deg2 survey by IXO should uncover ~ 200 AGNs with EWs > 100 eV between z=0.05 and z=0.5 Ballantyne (2010)
How to Look for Spin Evolution Including narrow line No narrow line Ballantyne (2010, in prep)